


Trading Up

by GrumpyBookworm



Category: Shadowhunters (TV)
Genre: Alternate Universe - Canon Divergence, Bodyswap, Chaos, Gen, Homophobia, How Do I Tag, I Don't Even Know, M/M, Oneshot, Other Additional Tags to Be Added, Spoilers, Tags Are Hard, The premise intrigues me, may turn into a series, sleeping potion
Language: English
Status: In-Progress
Published: 2017-06-13
Updated: 2017-06-15
Packaged: 2018-11-13 13:58:50
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 4,340
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11186571
Author URL: https://archiveofourown.org/users/GrumpyBookworm/pseuds/GrumpyBookworm
Summary: *Takes Place during 2x12*When Jace gets invited over to Magnus's he's expecting many things. He's certainly isn't expecting what comes next.





	1. The Worst Wine Tasting Ever

**Author's Note:**

> Disclaimer: I do not own the Mortal Instruments books nor do I own the Shadowhunters TV show. They are owned by Cassie Clare and Freeform respectively. 
> 
> This premise came into my head as soon as I saw the episode. I just had to write about it. If I enjoy the premise I may keep going but for now this is considered a one-shot. Let me know if this is something you would like to see more of. This is something I might like to continue with.
> 
> -Bookworm101234

Jace adjusted his leather jacket as he knocked on Magnus's door. He had been a tad bit surprised to see the text from Magnus on his phone. They were friendly sure, but he wouldn't say they were close exactly. The only thing the two had in common was their shared love for Alec. But granted the warlock had let Jace stay with him when he was on the run with Valentine, and that meant a lot to him. He wasn't sure why he had shown up anyways. There were other things he could be doing. He could be watching over Valentine to be sure that he wasn't playing anymore tricks. He could be training. With the discovery of his angel blood, Jace was curious to discover what his power would be exactly. He shook himself out of his thoughts as the door to Magnus’s began to open. 

“Jace. Thank you so much for coming.” The warlock said. Jace took in the sight that was Magnus Bane. His hair was coiffed to perfection. Jace had always felt that hair was an important part of a person. He had always felt like his blonde locks were an important part of who he was. Though he didn’t know much about makeup, all his years of growing up with Isabelle had taught him that Magnus was rocking an intense smoky eye. Magnus’s outfit seemed to be typical for him, if not a bit darker than usual. 

“Yeah of course.” Jace said as he entered Magnus’s apartment. Magnus pushed him forward out of the hallway and into the foyer of his apartment. As Magnus was closing the door, Jace took another glance at the warlock. Jace could see why Alec had fallen for him. There was something about the way he carried himself that made him so sexy. While he didn’t feel attraction toward guys in the way that Alec did, he was always one to appreciate a beautiful man. Magnus was certainly a gorgeous man. 

“Uh so what’s this surprise you want me to help plan for Alec,” Jace asked, “I hope there's liquor involved.”. He could feel the smirk rising on his face at the mention of liquor. If there was one thing that Jace was down for, it was a Magnus Bane party with good alcohol. The warlock was famous, or infamous depending on who you asked, for his raging parties. Jace had even heard some vampire once say that his parties were like something out of some book called The Majestic Gatsby or something. 

Jace was slightly unnerved by the way Magnus was looking at him. He seemed to be sizing him up for something. Jace knew he was an attractive guy, but he was a bit uncomfortable with his brother’s boyfriend staring at him so intensely. 

“What’s up?” Jace asked. If there was something going on with Magnus, Jace would want to know about it so he could help. After all the drama that he and Alec had gone through over the past few months, it was the least he could do. 

“Nothing,” The warlock replied, “It’s just nice being like this. Like friends. It’s a shame that it has to end.”

At this Jace was confused. Unless Magnus had done something unforgivable, there was no way that their friendship would be ending anytime soon. 

“What?” Jace asked as he furrowed his brows. 

“Oh never mind that. It’s just that eventually you all will die and I will alone. It will be nice to know that there are Shadowhunters out there who do care about us Downworlders.” Magnus said as he turned around to go grab something from a table nearby. 

“Magnus, we have quite a while until that happens. There’s no need to be so morbid. I mean I know I’m a great person but there's no need to start planning my funeral.” Jace said. He was glad that it was just Magnus being morbid. For a moment there he thought that Magnus had turned on them all. 

Magnus returned with two crystal goblets that were filled with a mysterious liquid. He handed one to Jace which he kindly received. It was at moments like this that he was glad that he was in a place like New York. It would be easier to find a way back to the Institute while he was drunk in a taxi, than if he were actually driving. 

“Anyways, I was wondering if you would try this drink with me. I was going to surprise Alexander with it. It’s a special wine from Tokyo. When we went on our date there, he wouldn’t stop talking about how much he was dying to try it.” Magnus explained. 

Jace nodded at this in surprise as he said “Really? You actually got Alec to have a conversation for more than five minutes? I’m impressed.”

“Well anyone can talk under the right circumstances.” Magnus replied in return. 

“Enough small-talk. We have a wine to try.” Jace said. 

“Yes we do. Cheers!” Magnus said cheerfully, quite a change from the somber mood he had been in earlier. 

“Cheers.” Jace replied. 

As Jace took a sip of the wine, he immediately sensed that something was wrong. This tasted like no wine Jace had tasted before. It tasted almost like a….potion? Jace could have sworn that he heard a whispering sound from behind him. But before he could react, he felt a pulling sensation in his core. He felt a whooshing sensation as his mind began to blur. The next thing he saw was himself? He was smirking evilly at him. Jace looked down at his hands only to find that they were covered in black nail polish. But before Jace could react, his eyes began to droop. He felt his body collapse to the floor. The last thing he saw before his eyes closed was his own body laughing in evil delight at him. And with that final visual in his mind, Jace feel into a deep slumber. 

*************************************************************************************

Jace really was right. He was a handsome guy. Valentine fluffed Jace’s leather jacket as he took a glance in that filthy warlock’s mirror. His attention turned to the Downworlder in the corner. If there was one that Valentine had appreciated about being in that disgusting warlock, it was his influence. Magnus Bane had tremendous power over the warlocks in Brooklyn. It had been quite easy to find a random warlock teen and convince him to mutter a few words as he and Jace drank the potion. 

“Um Magnus sir? You promised that you would give me a position of power if I helped you? I was just wondering when that would come?” The boy asked. 

“It’s coming.” Valentine said in Jace’s voice. Valentine liked the sound of Jace’s voice. It was pleasant and charismatic. It made people want to get to now him. 

“When?” The boy asked. 

“Now.” Valentine said. He took a knife out of Jace’s jacket and sent it flying into the creature’s heart. The boy’s eyes went wide in shock as he collapsed to the ground. After all these years, Valentine’s aim still was on-point. Granted the youthful energy that Jace’s body had didn’t hurt either. 

Valentine’s attention went from one disgusting warlock to another. Ever since he had been put into Magnus’s body, Valentine had been dying for a way out. When he had found a spell for swapping bodies, Valentine knew he was in business. The first option had been to swap places with Alexander Lightwood but there was no way that he was going to spend any moment in that fag’s body. Yes. Jace Herondale was the perfect specimen. And with the fact that he had been able to combine a sleeping potion with the body swapping potion made things all the more better. Now he wouldn’t have Jace running around telling his stupid friends about the situation. He kicked the warlock’s head just to be sure that he was asleep. He was. 

A knock at the door took Valentine away from his thoughts. He was pretty sure he knew who it was, but he shoved the sleeping Shadowhunter behind a couch. He went to answer the door. He opened it to find a tall blonde man with handsome features at the door. But it wasn’t the man that Valentine was focused on. It was his own body sleeping peacefully like a baby that made Valentine smile. 

“I see you traded up Father.” The man said. 

“Why yes I did son,” Valentine said in Jace’s buttery voice, “Yes I did.”


	2. Let's Get Down to Business

**Summary for the Chapter:**

> With Jace's body in Valentine's control, Valentine clears up some loose ends before he can begin his master plan.

**Notes for the Chapter:**

> Disclaimer: I do not own the Mortal Instruments books nor do I own the Shadowhunters TV show. They are owned by Cassie Clare and Freeform respectively.
> 
> First off, thank you for all of the attention that the story has gotten. I loved this premise so much that I had to continue the story. Feel free to comment with ideas and constructive criticism or if you just wanna discuss the show! I do have a general idea of where the story is going but I am open to interpretation.

Valentine gestured for Sebastian to put his own body down gently on one of that filthy warlock’s stupid couches. He may not like who’s in his body right now but he still wanted to treat it with delicacy. After all, he eventually would want to return to his own body. Just not yet. There were somethings that Valentine had to achieve while he was in Jace’s body. 

“How did you manage to get my body here? I doubt the Inquisitor would just let you walk off with such a dangerous criminal” Valentine asked. He still was not used to hearing Jace’s voice. This would take some getting used to. 

“You’d be surprised how easy it is to fool people if you have the shapeshifting rune.” Sebastian replied while lounging besides Valentine’s own unconscious body. 

“Who did you impersonate? And I hope that they won't return anytime soon” Valentine asked again. This plan needed to go perfectly. If there was one misstep, all that he had worked for would come crashing down. 

“Inquisitor Herondale of course. Let’s just say that she won’t be bothering anyone anymore. She’s on an extended vacation, if you catch my drift.” Sebastian replied in a cool manner. 

“But that doesn’t answer the question. How did you manage to steal the filthy warlock parading around in my body.” Valentine said. He was pleased to finally hear proper words coming out of the boy’s mouth. Though Jace wasn’t his biological son, he had loved him like one. He was not fond of his children’s desires to fraternize with Downworlders. It was something that he would have to work on. 

“I simply told the Institute that Valentine needed to be questioned in a private facility unbeknownst to the Clave. The Clave may be powerful but they have the intellect of a rabbit. I trust that you can piece together what happened next.” Sebastian said. 

Valentine could. Sebastian had snuck into Valentine’s cell. He had probably made a little chitchat with the disgusting Downworlder for a bit. Once it was clear that they were done, Sebastian had injected the warlock with the same sleeping potion that he had used on Jace. If there was one thing that Valentine had been happy about while being trapped in that filthy warlock, it was the fact that he could use magic. 

“Have you thought about what you’re planning to do with the warlock’s friends. They’re particularly devoted to him.” Sebastian asked his father. 

“Yes I have. In fact, I’ve spent all day preparing for it. When ‘Jace’ returns to the Institute, I will tell that fag parabatai of his that the warlock had to go on an emergency outing with no clear return date. I will send texts and photos to the boy from Magnus’s phone to make it seem like he’s actually there.” Valentine said. 

“And if the boy disbelieves it?” Sebastian asked. 

“I have a backup plan. Don’t worry son. I didn’t get as far as I did without planning ten steps ahead,” Valentine said, “Besides all of the warlock and Jace’s friends are idiots. Even my own daughter, Clarissa.” 

At the mention of his sister, Sebastian tensed. Valentine had explained why they couldn’t reveal his true parentage yet. But it was extremely clear that it was still hard for Sebastian. Valentine rolled his eyes as he went over to examine his hair in the mirror. Jace liked to keep it long for some reason. Valentine didn’t understand why. But still, he smoothed back the long blonde locks. Sebastian coughed, making it clear that he had more to talk about. 

“What are we going to do with the bodies?” Sebastian asked. His son had a good point. They couldn’t just leave the bodies here. Someone would show up and notice the fact that the bodies of Magnus Bane and Valentine Morgenstern were sleeping next to each other. 

“Don’t worry, I have a guy coming.” Valentine said. 

As soon as Valentine said this, a portal opened up. A young man stepped out. He had green skin and blue feathers for hair. Valentine sneered at the warlock. Valentine went down to pick up the body that contained a sleeping Jace. Sebastian did the same with Magnus. Valentine and son stepped through the portal only to find themselves in the middle of a field. 

“Where in the bloody hell are we?” Sebastian asked. 

“A field in Idaho.” The warlock replied. 

“Why?” Sebastian asked. 

“That’s why.” Valentine said. He gestured to two open caskets laying in a deep hole. If Valentine had to guess, the hole had been dug by magic. There was no way someone could dig a hole that perfect and still look like they just walked off the runway. 

“So that’s the plan. We’re just going to plop the bodies in a hole in the middle of the United States and hope that no warlock can sense it? Seems risky.” Sebastian said. 

“Once the bodies are in the caskets, I’ll fill the hole back up and place powerful wards over it. No one in the Shadow world will be able to find them.” The warlock explained. 

Valentine gestured for the warlock to put the caskets in front of him. The warlock rolled his eyes as he did it. Valentine opened one of them and gestured for Sebastian to lay his body in there. Once the action had been done, Valentine leaned over it and took one last look. Even with a disgusting downworlder in his place, his body still looked handsome. Valentine adjusted the navy jumpsuit that his body wore and used his thumb to wipe off the blood on his forehead. He wanted his body to look his best no matter what. Valentine grabbed his body’s arms and laid them down gently in front of him. Once Valentine was done, he gently closed the casket and made the motion for the warlock to set it in the hole. 

With that done, Valentine turned to the filthy Downworlder’s body. He kicked Magnus’s head again as well as stepped on his face with Jace’s tough sneakers. He picked up the body and threw it in the coffin. Magnus’s body landed with his ass up in the hair and his face lying down facing the padded edges of the casket. Valentine stomped on Magnus’ s ass in order to straighten out the body. Valentine was satisfied as he was pretty sure that he heard a crunch come from Magnus’s face. Valentine closed the door to the coffin and kicked it until it fell into the hole with a thud. The warlock filled up the hole and cast the wards as Valentine gestured for his son to follow him through the portal. 

“There’s just one more thing you have to do.” Valentine said. 

“And then I will have fulfilled my mission?” The warlock asked. 

“Yes. You will erase our memories of where the bodies are located. Everyone’s. Me, Sebastian, and your own. If we don’t even know where the bodies are, how can anyone know?” Valentine said rhetorically. 

“Wait what?” Sebastian asked. 

Before Valentine could respond, the warlock began to cast the spell. A green mist came out of his fingers and surrounded Sebastian and Valentine’s heads. Valentine could feel the thoughts of where the bodies were leaving his mind. Judging from the look on Sebastian’s face, he was forgetting too. After the warlock had finished his spell, Valentine took out a dagger from Jace’s jacket and slit the warlock’s neck. The fewer people who knew about the events of tonight, the better. 

“Was that really necessary?” Sebastian asked. 

“Yes it was. We couldn’t have him running around knowing what was going on. He could have sold that information to the Shadowhunters.” Valentine explained. 

“Whatever. Anyways what's our next move? Now that you’re Jace you’re going to have to live his life without a mess-up.” Sebastian said. 

“Your next move is to dispose of these bodies, and don’t worry about me. I’m sure I can handle living the life of a cocky douchebag like Jace.” Valentine said. 

“So I’m on cleanup duty. Great.” Sebastian said unenthusiastically. 

At this Valentine turned around and left his son to do the work. But before he left, he took one last look in the mirror. Jace truly was a handsome guy. Jace’s broad shoulders and handsome features combined with Valentine’s charismatic personality, he would be an unstoppable force. As Valentine fluffed Jace’s jacket, he felt something vibrating in Jace’s back pocket. He took it out to see that Alec was calling him. 

Picking up the phone, Valentine said “Hey Alec! What’s up?”


	3. The First Test

**Summary for the Chapter:**

> Valentine is thrown into the deep end as he now has to prove if he has what it takes to be Jace Wayland.
> 
> I suck at summaries LUL

**Notes for the Chapter:**

> Disclaimer: I do not own Shadowhunters or The Mortal Instruments. Those belong to Freeform and Cassie Clare respectively. 
> 
> First off, thank you so much for all of the attention that this story has gotten. I never thought that this would get as many hits as it did. 
> 
> Secondly, I apologize if the chapters are still semi-short and if it seems like not much is going on. I'm still getting my bearings with working with these characters. So I'm taking it slow for now. 
> 
> And with that, don't forget to leave kudos, A Review with Constructive Criticism, and maybe a subscribe or bookmark. 
> 
> I hope you all have a great day, enjoy the chapter, and I'll see you next time.   
> -Bookworm101234

As Valentine approached the doors of the New York City Institute, he took a deep breath. This was his first real test to prove that he could BE Jace Wayland. It wouldn’t be easy either. He would have to prove it to people who have known Jace for a long time. Valentine reassured himself with the fact that he had helped raise Jace when he was a boy. He smoothed back Jace’s hair and prepared himself for the onslaught that would arrive as he entered the Institute. He opened the door and stepped into the Institute. As Valentine walked into the main hub of the building, he appreciated the work that Robert and Maryse had achieved in turning into a top tier military facility. 

“Jace! There you are!” A feminine voice called. 

Valentine turned to see his daughter running towards him. He released a breathe that he didn’t know he was holding as he watched her run towards him. Valentine was shocked each time he saw her about how much she looked like Jocelyn. The thought of his former wife made his heart her just a little bit. As Clarissa, no Clary, came up to him he made sure to look brooding and semi-depressed slash bored. That was the usual look he saw Jace wear when he was around Clary. 

“Clary, were you looking for me?” Jace asked. 

“The whole Institute’s been worried sick looking for you. With the Inquisitor taking Valentine randomly and all of the stuff he was saying, You kind of slipped through the cracks. Where were you?” Clary asked. 

Valentine thought carefully about what he had to say. If he revealed that Jace had gone over to Magnus’s, then that would draw attention to the missing warlock. Valentine already had to try to explain to Alec why his lover wasn’t around. He didn't need anymore problems on that front. He also had to take into consideration Jace’s relationship with Clary. From the intel he had gathered, Jace and Clary now knew that they weren't related. Clary was dating her vampire nerd friend, and Jace was left to stare longingly from the sidelines. Because Valentine didn’t want to have to start making out with his own daughter, he made the executive decision to squash any romantic feelings his daughter had for Jace. Even though Valentine wanted to vomit at the thought of his daughter dating a filthy Downworlder, he would much rather have Clary be with that thing than have to kiss his own daughter as Jace. He would have to come up with something that would throw people off of his tail, push Clary towards the vampire, and still stay in character for what Jace would do. 

“I was just following a lead as to where the Mortal Cup could be.” Valentine said, hoping that Clary would step right into his trap. 

“Really? Did you find anything?” Clary asked, she had stepped in it. 

“No we got a bit..sidetracked if you catch my drift.” Valentine said. He even threw in a wink and a smirk to lay it on thick. 

“Classy Jace. Real classy, ” Clary said with an eye-roll, “Your family has been worried sick about you, and you’ve been off having sex?”

“Why do you care so much Clary? You have a boyfriend, if I recall?” Valentine said. He could see why Jace and Clary had so much chemistry. This banter they had just came naturally. Valentine was surprised at how easy it was to slip into that role. 

“Your family was just worried that’s all.” Clary said.

“Mm well thanks for telling me.” Valentine said, making it clear that the conversation was over. 

“No problem. Izzy wanted me to tell you that Alec wanted to see you in the training area” Clary said as she started to run off. If Valentine had to guess, she was running off to meet her boyfriend.   
“I know. I already got an earful from Alec on my way over here.” He replied as he started to run off. 

When he got to the training room, Alec Lightwood was pacing across the room. Luckily for Valentine, Alec hadn’t seen him yet. This allowed for him to get a better glimpse of the man. During his tenure in Magnus’s body, he had been extremely uncomfortable around Alec. But now that he was in the body of a Shadowhunter, Valentine felt more comfortable around the eldest Lightwood. Despite his hatred at Robert and Maryse for abandoning the Circle, he had respect for the way they had managed to tighten the reins on their children to an extent. Valentine took a glance at Alec. He was definitely the product of his parents. He had the Lightwood looks as well as their strict upbringing. Valentine took yet another deep breath and entered the room. 

“Hey Alec! What did you want to see me about?” Valentine asked. 

“Hey Jace. It’s just that I haven’t heard from Magnus since this morning. With the way both he and Valentine have been acting, I’m just not sure right now about what’s going on.” Alec said. 

“Magnus is the High Warlock. I’m sure he’s extremely busy with clients and stuff. And as for Valentine, the Inquisitor has him now so there’s no need to worry. We can just go back to focusing on demon-hunting and being parabatai.” Valentine said. He had made sure to try to sound as charismatic as possible. Alec was the one person here who he desperately needed to convince. He could wing it with Clary and Isabelle, but Alec was another animal entirely. 

“I just find it odd. Magnus promised that he would call me later.” Alec said again. 

“Hey do not be THAT guy.” Valentine said. 

“What guy?” Alec asked. 

“The one who calls their partner a thousand times because they’re uncomfortable about the state of their relationship.” Valentine said. He may not have been young for a while but Valentine was able to remember the stress involved with young love. He also felt like that would be something Jace would say. It was also important that he keep Alec as ignorant as possible for what was truly going on. 

“I’m not being that guy. I’m worried!” Alec said defensively. 

“Really?” Valentine said. He had to admit that he found this kind of ironic. In the past day, Alec has spent more time with Valentine than he had with he actual owners of the bodies he had been in. 

“Okay I MAY be that guy right now. And are you ok? This is something Izzy would badger me about not you?” Alec asked. If Valentine listened closely, he could gear the teeniest amount of suspicion in his voice. 

“Yeah I’m fine man. I’m just a little out of it after my reconnaissance mission with ….” Valentine began to say. It was then that he realized that he didn’t know who Jace’s other sexual partners were. He hoped that Alec would be able to fill in the blanks. 

“Oh god you were with Kaelie again weren’t you? Jace how many times do I have to tell you Seelies are bad news. It only took Izzy about five hundred times. How many times will it be for you? Six to seven hundred?” Alec asked in an annoyed matter. This is clearly something that they had argued about before. 

“Whoa Alec! Chill with the riot act ok! I just needed to let off a little steam ok? Now if you’ll excuse me, I’ve had a long day and would like to get some rest.” Valentine said. And with that, he walked off to Jace’s room. Though Valentine had never been in the family wing of the Institute, it wasn’t hard to figure out who’s was who’s. The Lightwood’s daughter’s room was the one with the flashy door. Alec’s was right next to hers. Robert and Maryse’s room was the one with the double doors. Valentine turned to the other room in the hall. He opened it cautiously. Judging by the military-level efficiency, this had to be Jace’s. Valentine walked around the boy’s room. It was extraordinarily neat. Everything was in it’s place with little clutter. Valentine took a peek inside the closet. It consisted of white t-shirts, jeans, black leather jackets, and Shadowhunter Gear. 

Valentine turned his head as he heard the sound of a door opening. He looked to see Maryse Lightwood standing in the room. He was shocked at how well she had aged. She still looked like the intense young woman she had been while they were in the Circle together. But this was not his Maryse, this was Jace’s pseudo-mother. He raised his arm to wave hello, but Maryse ran up to him and slammed him against the wall. 

“What the hell!” Valentine yelled in shock. 

“Who are you and what the hell did you do with my son?” Maryse asked intensely.


End file.
